Hydrogen fluoride is a well-known compound that is used in industry in a variety of processes including in alkylation reactions as a catalyst, in fluorination reactions as a fluorinating agent, in the manufacture of fluorides, in the separation of uranium isotopes, in the production of fluorine containing plastics, and in etching and cleaning applications. It is well known that hydrogen fluoride is a volatile, extremely hazardous substance the high vapor pressure of which renders it readily aerosolizable.
In an attempt to diminish the hazards of hydrogen fluoride, it has been combined with a variety of substances. U.S. Pat. No. 1,470,772 discloses a glass etching paste of mucilage, sulfuric acid, and ammonium fluoride in which the hydrogen fluoride is formed in situ. U.S. Pat. No. 3,635,836 discloses dispersions of hydrogen fluoride, particulate proteinaceous material and a small amount of carboxyl substituted vinyl polymers useful as pickling agents, plumbing cleaners and paint removers. U.S. Pat. No. 4,383,868 discloses a method of treating anhydrous hydrogen fluoride spills by applying a particulate mixture of polyacrylamide and a polyalkyl(alk)acrylate to the surface of the spill. However, none of these compositions provides an intimate mixture of hydrogen fluoride and a substance that both reduces the hazards of hydrogen fluoride and, at the same time, permits the ready recovery of the hydrogen fluoride from the composition.
To overcome these problems, it has been suggested to provide a mixture of hydrogen fluoride and water-soluble polymer. For example, U.S. Pat. No. 6,177,058 describes gelatinous mixtures of hydrogen fluoride (HF) and sodium polyacrylate or polyacrylamide. U.S. Pat. Nos. 7,914,761 and 8,153,096 describe mixtures of hydrogen fluoride and a polyacrylate-polyacrylamide cross-linked polymer.
Improvements in the foregoing processes and compositions are desired.